border-bottom-1px($color)
	position: relative
	&::after
		display: block
		position: absolute
		left: 0
		bottom: 0
		width: 100%
		border-top: 1px solid $color	
		content: ' '
border-top-1px($color)
	position: relative
	&::before
		display: block
		position: absolute
		left: 0
		top: 0
		width: 100%
		border-top: 1px solid $color	
		content: ' '
bg-image($url)
	background-image: url($url + "@2x.png")
	@media ( -webkit-min-device-pixel-ratio: 3),(min-device-pixel-ratio: 3)
		background-image: url($url + "@3x.png")

border-none()
	&:after
		display: none